1. Field of the Invention
The present invention relates to a method and apparatus for measuring at least one transfer impedance of shielded devices and common mode currents in shieldings.
2. Brief Description of Prior Developments
Increase in signal speed and guidelines for Electromagnetic Compatibility require methods and apparatus for determination of shielding effectiveness. In IEC TC46/WG5 it was proposed that the transfer impedance be the measure for shielding effectiveness.
Several methods and apparatus for measuring the transfer impedance are known, e.g. the matched triaxial, wire injection and mode-stirred chamber method. However, they are essentially only suitable for shielded cables, require very high investments or are difficult to use.
The primary object of the invention is to provide a transfer impedance measurement method and apparatus for carrying out such a method which are easy to use and do not need any high investment.
Another object of the invention is to provide a method and an apparatus for measuring a common mode current through a shielding system, having any desired form, of a shielded device which method can be used to measure transfer impedances.
A further object of the invention to provide such a method and apparatus which can, for instance, easily be used to measure at least one transfer impedance of connectors for any number of contact members or their position within the connector body.